Communication between a calling party and a called party may be established over a communication network. Such a communication network may include a plurality of network switches that transport data. In typical cell-based and packet-based communication networks, these switches include a switch core and a number of line cards. Each of the line cards provides a communication link to another switch in the network. The switch core allows inputs received from one line card to be provided on the output of another line card. This flexible routing of data allows for efficient communication between the various switches in the network.
In operation, line cards within a switch may experience faults or other errors that cause the line card to fail. In such instances, it is desirable to have a redundant line card that can be switched into an active mode and utilized to insure that data communication with the network is not interrupted. However, in order to provide a redundant line card for each line card in the system, prior art systems required that the effective bandwidth of the overall switch be cut in half. This is due to the fact that switch cores within the switch are only able to couple to a limited number of line cards. As such, if redundant line cards are included in the system, some of the coupling capabilities of the switch core will be consumed by these redundant line cards. As the redundant line cards are only utilized in the event of a problem with the normally active line cards, the bandwidth of the overall switch is effectively halved.
Another prior art solution includes an additional switch core in the system, where the additional switch core is coupled to a complete array of line cards. These line cards are coupled to the external data connections in the same manner as the line cards of the original switch core. When an error occurs with one of the line cards coupled to the original switch core, the entire system switches over to utilize the additional switch core provided in the system. However, this transition effectively eliminates any future redundancy for all of the line cards in the system. In addition to this, including an additional switch core within the switch adds to the cost and complexity of the switch.
Therefore, a need exists for a method and apparatus for providing line card redundancy in a communication switch without reducing the effective bandwidth of the switch.